SSL_CTX_set_tmp_dh is used to set the Diffie-Hellman parameters for a context. One of the easiest ways to get Diffie-Hellman parameters to use with this function is to generate random Diffie-Hellman parameters with the dhparam command-line program with the -C option, and embed the resulting code fragment in your program. For example, openssl dhparam -C 2236 might result in: